Hox homeodomain proteins exhibit selective complex stabilities with Pbx DNA

Wei Fang Shen, Ching Pin Chang, Sofia Rozenfeld, Guy Sauvageau, R. Keith Humphries, Ming Lu, H. Jeffrey Lawrence, Michael L. Cleary, Corey Largman

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

Eight of the nine homeobox genes of the Hoxb locus encode proteins which contain a conserved hexapeptide motif upstream from the homeodomain. All eight proteins (Hoxb-1-Hoxb-8) bind to a target oligonucleotide in the presence of Pbx1a under conditions where minimal or no binding is detected for the Hox or Pbx1a proteins alone. The stabilities of the Hox-Pbx1a-DNA complexes vary >100-fold, with the proteins from the middle of the locus (Hoxb-5 and Hoxb-6) forming very stable complexes, while Hoxb-4, Hoxb-7 and Hoxb-8 form complexes of intermediate stability and proteins at the 3′-side of the locus (Hoxb-1-Hoxb-3) form complexes which are very unstable. Although Hox-b proteins containing longer linker sequences between the hexapeptide and homeodomains formed unstable complexes, shortening the linker did not confer complex stability. Homeodomain swapping experiments revealed that this motif does not independently determine complex stability. Naturally occurring variations within the hexapeptides of specific Hox proteins also do not explain complex stability differences. However, two core amino acids (tryptophan and methionine) which are absolutely conserved within the hexapeptide domains appear to be required for complex formation. Removal of N- and C-terminal flanking regions did not influence complex stability and the members of paralog group 4 (Hoxa-4, b-4, c-4 and d-4), which share highly conserved hexapeptides, linkers and homeodomains but different flanking regions, form complexes of similar stability. These data suggest that the structural features of Hox proteins which determine Hox-Pbx1a-DNA complex stability reside within the precise structural relationships between the homeodomain, hexapeptide and linker regions.

Original languageEnglish (US)
Pages (from-to)898-906
Number of pages9
JournalNucleic acids research
Volume24
Issue number5
DOIs
StatePublished - Jan 1 1996

ASJC Scopus subject areas

  • Genetics

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    Shen, W. F., Chang, C. P., Rozenfeld, S., Sauvageau, G., Humphries, R. K., Lu, M., Jeffrey Lawrence, H., Cleary, M. L., & Largman, C. (1996). Hox homeodomain proteins exhibit selective complex stabilities with Pbx DNA. Nucleic acids research, 24(5), 898-906. https://doi.org/10.1093/nar/24.5.898